Indeed (excerpt):
Washington’s Thanksgiving Proclamation, New York, 3 October 1789 — By the President of the United States of America, a Proclamation:
Whereas it is the duty of all Nations to acknowledge the providence of Almighty God, to obey his will, to be grateful for his benefits, and humbly to implore his protection and favor— and whereas both Houses of Congress have by their joint Committee requested me to recommend to the People of the United States a day of public thanksgiving and prayer to be observed by acknowledging with grateful hearts the many signal favors of Almighty God especially by affording them an opportunity peaceably to establish a form of government for their safety and happiness.
Now therefore I do recommend and assign Thursday the 26th day of November next to be devoted by the People of these States to the service of that great and glorious Being, who is the beneficent Author of all the good that was, that is, or that will be— That we may then all unite in rendering unto him our sincere and humble thanks—for his kind care and protection of the People of this Country previous to their becoming a Nation—for the signal and manifold mercies, and the favorable interpositions of his Providence which we experienced in the course and conclusion of the late war—for the great degree of tranquility, union, and plenty, which we have since enjoyed—for the peaceable and rational manner, in which we have been enabled to establish constitutions of government for our safety and happiness. (https://www.loc.gov/resource/mgw8a.124/?q=1789+Thanksgiving&sp=132&st=text)
And,
Congressional Thanksgiving Day Proclamation, November 1, 1777 — Forasmuch as it is the indispensable duty of all men to adore the superintending providence of Almighty God; to acknowledge with gratitude their obligation to him for benefits received, and to implore such farther blessings as they stand in need of;... It is therefore recommended to the legislative or executive powers of these United States, to set apart Thursday, the 18th day of December next, for solemn thanksgiving and praise; that with one heart and one voice the good people may express the grateful feelings of their hearts, and consecrate themselves to the service of their divine benefactor; and that together with their sincere acknowledgments and offerings, they may join the penitent confession of their manifold sins, whereby they had forfeited every favor, and their humble and earnest supplication that it may please God, through the merits of Jesus Christ, mercifully to forgive and blot them out of remembrance;...may render them fit instruments, under the providence of Almighty God...to take schools and seminaries of education, so necessary for cultivating the principles of true liberty, virtue and piety, under his nurturing hand, and to prosper the means of religion for the promotion and enlargement of that kingdom which consisteth in righteousness, peace and joy in the Holy Ghost. (http://www.wallbuilders.com/libissuesarticles.asp?id=3847)
And,
Congressional Thanksgiving Proclamation, 1782 — It being the indispensable duty of all nations, not only to offer up their supplications to Almighty God, the giver of all good, for His gracious assistance in a time of distress, but also in a solemn and public manner, to give Him praise for His goodness in general, and especially for great and signal interpositions of His Providence in their behalf; therefore, the Unites States in Congress assembled, taking into their consideration the many instances of Divine goodness to these States in the course of the important conflict, in which they have been so long engaged, - the present happy and promising state of public affairs, and the events of the war in the course of the year now drawing to a close;..Do hereby recommend it to the inhabitants of these States in general, to observe and request the several states to interpose their authority, in appointing and commanding the observation of THURSDAY the TWENTY-EIGHTH DAY OF NOVEMBER next as a day of SOLEMN THANKSGIVING to GOD for all His mercies; and they do further recommend to all ranks to testify their gratitude to God for His goodness by a cheerful obedience to His laws and by promoting, each in his station, and by his influence, the practice of true and undefiled religion, which is the great foundation of public prosperity and national happiness.
• Done in Congress at Philadelphia, the eleventh day of October, in the year of our LORD, one thousand seven hundred and eighty-two, and of our Sovereignty and Independence, the seventh. (http://www.wallbuilders.com/libissuesarticles.asp?id=17944)
More: http://peacebyjesus.witnesstoday.org/Quotes_compare.html